This invention relates in general to closure prostheses which might find application for transcatheter placement within the heart to close congenital and operative cardiovascular defects.
Examples of such cardiovascular defects include those which result in an abnormal opening in the cardiovascular system and permit deleterious shunting of blood thereacross, such as atrial and ventricle septum defects and patent ductus arteriosus. To minimize the risk of mortality associated with surgery, transcatheter techniques have been developed to introduce closure devices for sealing such defects. One example of such a device is described in Blake, U.S. Pat. No. 4,007,743. Blake discloses a pair of umbrella-like closure devices which include resilient ring sections to automatically open the struts of the umbrella as the devices are pushed out of their respective catheters. King et al., U.S. Pat. No. 3,874,388, similarly discloses a pair of umbrella-like closure devices which interconnect after placement to seal across a defect.
These and other such devices rely on the caudal and cranial ends of the device being larger than the opening of the defect itself to physically trap the device across the opening. To accommodate transcatheter delivery techniques, the resulting device configurations have become unduly mechanical in nature, often including multiple components or requiring sequential delivery. Also, many of these devices require assembly across the defect after delivery, thereby increasing the complexity of the transcatheter equipment and delivery process.
A need therefore exists for an improved closure device. Such a device would be of a compact, unitary construction, therefore permitting the device to be delivered intact using transcatheter techniques. Also, such a device would be delivered from a sheath or catheter in a one-step procedure, rather than requiring sequential delivery. Similarly, such a device would be manually controlled after delivery to ensure proper placement and sealing across the defect. Preferably, the device would also be self-centering to facilitate proper delivery and placement across the defect.